In recent years, traffic has rapidly increased along with the popularization of mobile terminals such as a mobile phone or a smartphone. Therefore, for the LTE (Long Term Evolution) scheme, microcell base stations which cover the relatively small communication regions (cells) with, for example, a radius of about a few meters to a few ten meters, as well as macrocell base stations which cover the relatively large communication regions with, for example, a radius of about a few hundred meters to a few kilometers, are installed. This microcell base station is installed at, for example, a region in which traffic concentrates, a coverage hole in which communication cannot be locally performed or the like within the communication region of the macrocell base station. By installing the microcell base station like this, the frequency usage efficiency is enhanced.
The communication between the macrocell base station and the microcell base station is performed using the X2 interface via a mobile backhaul. However, the inter-base-station communication is performed so that base stations which are logically adjacent are connected into a mesh form. Therefore, the data which is defined by, for example, the X2 application protocol (X2AP) is transmitted to the mobile backhaul or a core network. Thus, there is a possibility that the load of the mobile backhaul or the core network may increase.
With reference to the above-mentioned technique, for example, Patent Literature 1 discloses a system and a method for facilitating the inter-access-point communication by using an air interface which is the same as the one used for providing services to wireless devices.
Patent Literature 2 discloses a base station transceiver including a wireless interface which has a first coverage area surrounding a second coverage area of a second base station transceiver.
Non Patent Literature 1 discloses details of the X2 interface, which is an interface for the inter-base-station communication, and the X2AP.